Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2010-6-29
pubmed:abstractText
Water potentials of leaves and nodules of broad bean (Vicia faba L.) cultivated on a sandy mixture were linearly and highly (r(2) = 0.99) correlated throughout a water deprivation of plants. A decrease of 0.2 megapascal of the nodule water potential (Psi(nod)) induced an immediate 25% inhibition of the highest level of acetylene reduction of broad bean nodules attached to roots. This activity continued to be depressed when water stress increased, but the effect was less pronounced. Partial recovery of optimal C(2)H(2) reduction capacity of mildly water stressed nodules (Psi(nod) = -1.2 megapascals) was possible by increasing the external O(2) partial pressure up to 60 kilopascals. The dense packing of the cortical cells of nodules may be responsible for the limitation of O(2) diffusion to the central tissue. Bacteroids isolated from broad bean nodules exhibited higher N(2) fixation activity with glucose than with succinate as an energy-yielding substrate. Bacteroids from stressed nodules appeared more sensitive to O(2), and their optimal activity declined with increasing nodule water deprivation. This effect could be partly due to decreased bacteroid respiration capacity with water stress. Water stress was also responsible for a decrease of the cytosolic protein content of the nodule and more specifically of leghemoglobin. The alteration of the bacteroid environment appears to contribute to the decline in N(2) fixation under water restricted conditions.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Mar
pubmed:issn
0032-0889
pubmed:author
pubmed:issnType
Print
pubmed:volume
92
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
595-601
pubmed:dateRevised
2010-9-15
pubmed:year
1990
pubmed:articleTitle
Nitrogen Fixation (C(2)H(2) Reduction) by Broad Bean (Vicia faba L.) Nodules and Bacteroids under Water-Restricted Conditions.
pubmed:affiliation
Laboratoire de Biologie végétale et Microbiologie, URA CNRS 79-Parc Valrose, Université de Nice-Sophia Antipolis, 06034 Nice Cedex, France.
pubmed:publicationType
Journal Article